Air-compressor.



J. H. THOMAS.

AIR COMPRESSOR.

APPLICATION FILED APR.11, 1913.

2 SH BETS SHEET 1.

- V VIIIVENTUR. g I ofimlh/ 0M4, W A l; 0mm.

J. H. THOMAS.

AIR COMPRESSOR. APPLICATION FILED APR.11,19 13.

Patented Sept. 1, 1914.

2 SHEETS SHEET 2.

WIN/E8858 W m, ATTORNEK UNITED STATES rn'rnnr osrion.

JOHN H. THOMAS, OF BLOQMFIELD, NEW JERSEY, ASSIGNOR TQ THOMAS MOTIVEPOWER COMPANY, A CORPORATION OF NEW JERSEY.

AIR-COMPRESSOR.

Specification of Letters Patent.

Patented Sept. 1, 1914.

To all whom it may concern:

Be it known that 1, JOHN H. THOMAS, a citizen of the United States,residing at Bloomfield, in the county of Essex and State of New Jersey,have invented certain Improvements in Air-Compressors, of which thefollowing is a specification.

The objects of this invention are to pro.- vide an air compressor ofgreat efliciency which shall be simple and 1nexpens1ve to manufacture;to secure free and ample intake of air to the cylinder upon the reversestroke of the piston; to insure the entrance of such air to the cylinderwith the least possible resistance, and at the same time enable thecylinder to be completely emptied on each instroke of the piston; tosecure a simple construction not liable to break or get out of order; toenable the parts of the cylinder to be conveniently secured together andto the crank case, and to obtain other advantages and results as may bebrought out in the following description.

Referring to the accompanying drawings, in which like numerals ofreference indicate the same parts throughout the several figures, Figure1 is a central longitudinal section of a compressor of my improvedconstruction, showing the position of parts upon instroke of the piston;Fig. 2- isa similar sectional view illustrating a modified constructionof cylinder head and an open bed or supporting base; Fig. 3v is asimilar View showing the position of parts assumed upon reverse strokeof the piston, the detail structure being that shown in Fig. 2; Fig. 4is a section on line A--A of Fig. 2, looking in the direction indicatedby the arrows, to illustrate the piston valves, and Fig. 5 is across-section on line BB Fig. 2.

In said drawings, and particularly Fig. 1, 1 indicates the closed crankcase of an aircompressing pump of my improved construction, and 2 is acylinder body mounted thereon with its head made up of a cap 3 providingan interior annular valve-seat 11, and a central valve guiding support 5screwed into said cap. The said cap preferably has a peripheral flange6, and bolts 7 extend through said flange 6, the base flange 8 of thecylinder body and screw into the crank-case 1, as shown, to bind allsaid parts together. Inside the said flange 6. the cap projects into thecylinder, as at 9, and pro vides a partition 10 disposed transversely ofthe cylinder, which partition is centrally apertured and forms a valveseat 11. The valve support 5 screws into the interiorly threaded end 12of the cap'and provides interiorly of itself a central portion 13supported by radial arms 14 and bored longitudinally of the cylinder toform a slideway 15 for the stem 16 of avalve 17. Said valve 17 isadapted to move between the valve support 5 and the valve seat ll beingsuitably fitted to said valve seat to imperviously engage the same, anda spring 18 is arranged between the valve support 5 and the valve 17 tonormally seat the same. Adischarge pipe 19 leads from the end of thevalve support 5, preferably screwed thereinto as shownln While I preferthe construction of cylinder head just described, I do not wish to beunderstood as limiting myself thereto, and indeed I have shown in Figs.2 and 3 an-' other construction of cylinder head which may sometimes beused. In this modified construction, an annular flange 21 is formed uponthe inner wall of the cylinder 20 and this flange is centrally aperturedto provide a valve seat 22. A valve support 23 fits within the cylinderand rests upon said flange 21, said support having a central portion 24supported y arms 25 and providing a central slideway for the stem 26 0fa valve 27 lying between the valve support and flange'21 and adapted tobe normally seated by a spring 28. Said valve support 23 is held inplace by an annular portion 29 of the cap 30, which annular portionprojects into the cylinder forthat purpose, while a flange 31 of the capover-lies the end of the cylinder body and receives bolts 32, whichclamp the cylinder parts all to the base or crank support 33 of the pumpor compressor. Adelivery pipe 3 1 screws into the cap 30 to conduct thedischarge or compressed air from the pump.

Within the clinder of my improved pump or compressor, is a piston 35 andwhich piston is shown of the same construction in the various figures ofthe drawings, so that the following description of the piston reads ontothem all. Said piston 35 is arranged upon a piston' rod 36,andpreferably has the edge of its. front end beveled or conicallytapered, as at 3.7, the cylinder head having a corresponding bevel ortaper so that the inner end. of the piston. exactly fits the inner endof the cylinder, as shown. In the construction of. Fig. 1, this bevel 38on the cylinder head is formed by an integral flange 39 on the enteringpart 12 of the cap, contiguous to the side wall of the cylinder andprojecting from the partition 10 toward the piston. In Figs. 2 and 3,where the valve seat member 21 is integral with the cylinder,an integralfillet 40 in the angle between the side wall of the cylinder and saidmember afiords the desired bevel 41. Obviously, it could be secured inother ways."

The piston 35 is preferably hollow, as shown, and the face of its frontend is recessed, as at 12, to receive a main valve &5, which forms theend surface of the piston exclusive of its marginal bevel or taper 37just described. At the edge ofsaid recess 42, its wall slopes conicallyinward. to form a seat 4 3 for the correspondingly shaped margin 14 ofthe valve 15, and at the center of the recess is an aperture 46 in whichthe stem 47 of said valve fits slidably. A spring -18 on said stem,between a collar 49 at the end of the stem and the end wall of thepiston, normally seats the valve 15, and around the slideway for thevalve stem in the bottom of the recess 42 are openings 4 through thepiston end for the passage of air when the valve is opened.

Preferably, thestem 47 of the valve is hollow, with its passagecontinued through said valve and provided with a second valve 50 similarto the main Valve itself. This second valve has a stem 51 extendingslidably through a spider 52 in the passage of the main valve, andprovided beyond said spider with a spring 53 pressing against an endstop 54 of the stem to seat the valve. Obviously, as the piston 35 makesa reverse stroke both the main valve 45 and the second valve 50 willopen to admit air to fill. the cylinder, as shown in Fig. 3, and thusthere is a free and ample intake with minimum resistance and in theshortest possible time. It will be noted that the beveled edge 37 alsoassiststhe entrance of air in that it enables the inrushing draft toexpand in both directions, that is, toward the center of the cylinder aswell as toward its walls. Tue space formed by said beveled or recessededge 37 becomes filled with air against which the later inrushing airimpinges with less friction and creation of.

heat than would be caused by its contact with metal. v

As shown in Fig. l, I prefer to employ a closed era nk case 1, the samebeing provided with one or more inwz'u'dly opening check valves screenedas at 56, and through which check valve atmospheric air enters the crankcase upon instroke of the piston.

When the piston makes its reverse stroke, the check valves 55 close andair from the crank case is positively. forced through the valves 45, 50of the piston into the cylinder. Many benefits and advantages of myimproved invention may be secured, however, without using a closed crankcase, and in Figs. 2 and 3 I have shown a supporting base 33 which doesnot provide a closed crank case.

An important-advantage of my invention is that the pump or compressorcan be made very small and run at high speed, and still. there will bea-full and freeintake of air from the atmosphere. Indeed, this can becarried to such an extent'that the inrushof air upon intake and itssudden stoppage upon the piston reaching the end of its stroke will fillthe cylinder with air at a pressure slightly above atmospheric pressure, upon well-known principles. In this way. the instroke of thepiston produces maximum results, and since I provide for the end of thepiston to fit closely against the cylinder head at the inner end of eachstroke, so that complete expulsion is ob- 2. The combination with acylinder body and a piston therefor, of a cap for said cylinder having aflange seated upon the end of the cylinder and a portion projecting intosaid cylinder and providing a. trans verse partition with a valve seattherein, .a valve carrier mounted centrally in said cap and adapted toreceive a discharge pipe, a valve in said valve carrier normally engaging said valve seat and adapted to open outwardly. and means forsecuring said cap to the cylinder independent of said valve car rier.

The combination with a cylinder and a closed crank-case having aninwardly opening check valve in its wall, of a piston. in said cylinder,an inwardly opening valve having a stem slidably seated in the end ofsaid piston, saidvalve having a central longitudinal passage tln'oughits said stem, and a second inwardly opening valve in said passage.

JOHN H. THOMAS.

lVitnesses:

Tnonas N. Dnvnr, M. 1).. MILToN A. SMITH.

denies of this patent may be obtained for five cents each, by addressingthe Commissioner of Eatents,

Washington, I). C.

